Stores' Anti-Theft Gates Pose Danger to Pacemakers and Defibrillators

Washington Post (National News: Findings) Nov. 5, 1998

Magnetic fields created by anti-theft gates guarding store exits can make implanted pacemakers and defibrillators go haywire, sometimes with fatal results, doctors said yesterday.

In the first of two articles in today's New England Journal of Medicine, a 72 year-old man with a defibrillator implant, which automatically shocks his heart whenever it beats improperly, is reported to have suffered four unnecessary shocks as he stood near an anti-shoplifting gate. The electromagnetic field apparently fooled the defibrillator into thinking his heart was beating improperly.

An alert nurse pulled him away from the gate and probably saved his life, said a group led by Peter Santucci of the Rush-Presbyterian-St. Luke's Medical Center in Chicago.

In another case, two doctors trying to explain why a 30-year-old woman with a pacemaker felt nauseous, breathless and dizzy whenever she passed through electronic surveillance gates at stores discovered that the anti-theft devices made her pacemaker send out improper signals.

Not all types of anti-theft surveillance systems create the type of magnetic interference that can disrupt pacemakers, said the authors of the second report, Michael McIvor of the Heart Institute of St. Petersburg, Fla,. and S. Sridhar of Affiliated Cardiologists in Phoenix.

However, They warned, "patients with pacemakers particularly those who are dependent on them, should take care to minimize their contact" with such systems "by passing quickly through the gates."

About 400,000 electronic anti-theft surveillance devices are present in stores, libraries and other locations worldwide. Other sources of electromagnetic interference, such as slot machines and remote control devices for toys, are also known to disrupt devices designed to sense and correct erratic heart rhythms.